Method for controlling radio access bearer in a communication system

ABSTRACT

A radio access bearer in a mobile communication system is controlled by disposing a radio resource control layer having radio access bearers in a user side, disposing a radio link control layer, a media access control layer, and a physical layer in the user side beneath the radio resource control layer in succession, measuring a traffic volume of the media access control layer and radio link control layer in the user side by using the media access control layer in the user side to produce traffic volume measurements, comparing the traffic volume measurements to at least one of an upper critical value and a lower critical value provided to the media access control layer in the user side from a radio resource control layer in a network side of the communication system through the radio resource control layer in the user side of the system, and forwarding a comparison result and the traffic volume measurements to the radio resource control layer in the network side through the radio resource control layer in the user side, and controlling the radio access bearer in the user side through the radio resource control layer in the network side according to a result of the comparison.

This application claims the benefit of and is a Continuation Applicationof U.S. Ser. No. 11/072,251, filed Mar. 7, 2005, which is a continuationof U.S. Ser. No. 10/653,943, filed Sep. 4, 2003 (now U.S. Pat. No.7,236,794), which is a continuation of U.S. Ser. No. 09/609,644, filedJul. 3, 2000 (now U.S. Pat. No. 6,640,105), and claims priority toKorean Patent Application No. P1999-26688, filed on Jul. 2, 1999, theentireties of each of the above-recited applications are herebyincorporated by reference for all purposes as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a next generation mobile communicationsystem, and more particularly, to in a method for controlling a radioaccess bearer in a next generation mobile communication system.

2. Background of the Related Art

Recently, the Association of Radio Industries and Business (ARIB) inJapan, the European Telecommunications Standards Institute (ETSI) inEurope, the TI in the USA, the Telecommunications Technology Association(TTA) in Korea, and the TTC in Japan have planned a further evolved nextgeneration mobile communication system based both on the core networktechnology of the existing Global System for Mobile Communications (GSM)which serves for multimedia, such as audio, video and data, and radioaccess technology. These organizations have agreed on common researchfor suggesting a technical specification for the evolved next generationmobile communication system, a project named Third GenerationPartnership Project (3GPP). The 3GPP encompasses the following threetechnical research fields.

The first technical research field is the 3GPP system and service field,for researching system architectures and service capabilities based onthe 3GPP specification.

The second technical research field is the field of UniversalTerrestrial Radio Access Network (UTRAN). The UTRAN is a RAN (RadioAccess Network), including W-CDMA according to a Frequency DivisionDuplex (FDD) mode, and TD-CDMA according to a Time Division Duplex (TDD)mode.

The third technical research field pertains to a core network having athird generation networking capability, such as mobility management andglobal roaming, being evolved from the second generation GSM.

Of the Technical Specification Groups (TSGs) conducting such technicalresearch, the Working Group 1 (WG1) related to Radio Access Networks(RAN) suggests general technologies for the physical layer (Layer 1),and the Working Group 2 (WG2), defines a data link layer (Layer 2) and anetwork layer (Layer 3), both being at higher levels than the physicallayer, as a second radio layer (Radio Layer 2) and a third radio layer(Radio Layer 3), and suggests general technologies on the second andthird radio layers.

FIG. 1 illustrates a related art radio interface protocol architectureaccording to the 3GPP RAN. An air-interface protocol between UE (UserEquipment) and a network side (UMTS Terrestrial Radio Access Network,UTRAN) consists of layer 1, radio layer 2, and radio layer 3.

Referring to FIG. 1, a protocol architecture is divided into a controlplane (C-Plane) for signaling, and a user plane (U-Plane) fortransmission of information. The C-Plane has a Radio Resource Control(RRC) Layer at Layer 3, and a Radio Link Control (RLC) Layer and aMedium Access Control (MAC) Layer at Layer 2, a layer lower than theLayer 3, and a Layer 1 at a lowest layer. The U-Plane has the RLC andMAC at Layer 2, and the Layer 1, a layer lower than the Layer 2. TheLayer 1 provides a transport channel for upper layer(s) inclusive of theMAC. In this instance, depending on how information is transferred onthe air-interface, different transport channels are provided, i.e.,either a common transport channel or a dedicated transport channel isprovided.

The MAC provides the upper RLC with logical channels, which differdepending on the forms of information to be transported. That is, theMAC provides the data transfer service on the logical channels, forms ofwhich logical channels differ depending on the kinds of the datatransfer services provided by the MAC. In this instance, the forms ofthe logical channels differ depending on the forms of information to betransported, wherein, in general, control channels are provided wheninformation for the C-Plane is to be transported, and traffic channelsare provided when information for the U-Plane is to be transported.Besides this, the MAC provides radio resource reconfiguration and MACparameter reconfiguration services, which are served when the RRCrequests a radio resource reconfiguration or a MAC parameter change. TheMAC also provides a measurement report service, reporting traffic volumevalues, a service quality index, a MAC condition index, and the like tothe RRC. The MAC providing those services has many functions, includinga traffic volume monitoring function which informs the RRC of thetraffic volume on the logical channel. The RRC analyses traffic volumeinformation reported from the MAC, and determines switching for thetransport channels.

The RLC provides services for radio access establishment/or cancelation.The RLC also provides a service for transporting PDU (Protocol DataUnits) at the upper layer to which any protocol information, inclusiveof segmentation/reassembly functions, is not included. The RRC providesan information broadcast service, in which information is broadcast toall UE in an one area. The RRC also controls Layer 3 C-Plane signalprocessing between the UE and the UTRAN. That is, the RRC providesfunctions of establishment, sustenance, and cancelation of radioresource access between the UE and the UTRAN. Particularly, the RRCprovides functions of establishment, sustenance, or cancelation of radioaccess bearers, functions of assignment, reconfiguration, andcancelation of radio resources required for radio resource access (thebearer is a capability defined for a signal transfer on the radiointerface), and UE measurement report and report control functions,corresponding to the traffic volume monitoring function among thefunctions of the MAC. The measurements at the UE are controlled by theRRC, when the RRC informs the UE of an object, a time and a method ofthe measurement. Then, the RRC informs the UTRAN of the measurements atthe UE. The radio interface protocol layers explained up to now provideother various functions and services. In such an existing radiointerface protocol architecture, traffic volume at the RLC is monitoredat the MAC in the U-Plane, for the RRC to assign, sustain or cancelradio resources.

However, no detailed procedures for these functions are suggested yet,in fact. That is, as explained, what is described in the 3GPP RAN isonly that a RLC traffic volume in a current user system is monitored atthe MAC, and only that radio access bearer control procedures, such asbearer reconfiguration, and channel reconfiguration are carried outaccording to the traffic volume monitoring at the MAC, without anysuggestions for detailed procedures for carrying this out.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a method forcontrolling a radio access bearer in a mobile communication system thatsubstantially obviates one or more of the problems due to limitationsand disadvantages of the related art.

An object of the present invention is to provide a method forcontrolling a radio access bearer in a mobile communication system, forcontrolling a radio bearer according to traffic volume more accurately.

Another object of the present invention is to provide a method forcontrolling a radio access bearer in a mobile communication system, forefficient management of radio resources according to traffic volume in aradio interface protocol.

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention. Theobjectives and other advantages of the invention will be realized andattained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with thepurposes of the present invention, as embodied and broadly described, amethod for controlling a radio access bearer in a mobile communicationsystem, comprising: (1) disposing a radio resource control layer havingradio access bearers in a user side of the communication system; (2)disposing a radio link control layer, a media access control layer, anda physical layer in the user side beneath the radio resource controllayer in succession; (3) measuring a traffic volume of the media accesscontrol layer and radio link control layer in the user side by using themedia access control layer in the user side to produce traffic volumemeasurements; (4) comparing the traffic volume measurements to at leastone of an upper critical value and a lower critical value provided tothe media access control layer in the user side from a radio resourcecontrol layer in a network side of the communication system through theradio resource control layer in the user side of the system, andforwarding a comparison result and the traffic volume measurements tothe radio resource control layer in the network side through the radioresource control layer in the user side; and (5) controlling the radioaccess bearer in the user side through the radio resource control layerin the network side according to a result of the comparison.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

In the drawings:

FIG. 1 illustrates a diagram showing a related art radio interfaceprotocol architecture according to the 3GPP RAN;

FIG. 2 illustrates a diagram showing a system of protocol entities forexplaining a procedure for controlling an active radio access bearer inaccordance with a preferred embodiment of the present invention;

FIG. 3 illustrates a diagram showing a procedure for monitoring trafficvolume for controlling an active radio access bearer in accordance witha preferred embodiment of the present invention;

FIGS. 4A-4C illustrate states of buffers in protocol entities forcontrolling an active radio access bearer in accordance with a preferredembodiment of the present invention;

FIG. 5 illustrates another system of protocol entities explaining aprocedure for controlling an active radio access bearer in accordancewith a preferred embodiment of the present invention; and,

FIG. 6 illustrates a flow chart showing a process for monitoring trafficvolume for controlling an active radio access bearer in accordance witha preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. FIG. 2 illustrates a diagram showing a system of protocolentities for explaining a procedure for controlling an active radioaccess bearer in accordance with a preferred embodiment of the presentinvention, particularly, a state before a transport channel is switchedin conducting traffic volume monitoring, and an initial state of theMAC. The MAC is disposed by the RRC including radio access bearers RAB1,RAB2 and RAB3 multiplexed into dedicated channels DCH1, and DCH2. Thededicated channels DCH1 are DCH2 are multiplexed into a Coded CompositeTransport Channel (CCTrCH). After disposing the radio access bearers,the RRC disposes the lower three layers of the RLC, tkdrl, and MAC, andthe physical layer (hereafter called as “PHY”). When these lower threelayers are disposed, the RRC provides a disposal request primitiveCMAC_configure_REQ to the MAC, which includes: first, radio accessbearer identification (ID), second, a logical channel ID, which ismultiplexing information, a transport channel ID, and a logical formatpriority according to a service quality (QoS), and third, a transportformat combination set, which is transport channel information. Uponcompletion of disposal of the lower three layers, the RRC requests theMAC to carry out a traffic volume monitoring function.

FIG. 3 illustrates a flow of messages showing a procedure for monitoringtraffic volume in accordance with a preferred embodiment of the presentinvention.

Referring to FIG. 3, before the process for monitoring traffic volume,the UTRAN-RRC provides a system information message to the UE-RRCthrough a BCCH (Broadcasting Control Channel) (S1), and a MEASUREMENTCONTROL message through a Digital Control Channel (DCCH). (S2).Eventually, the UE-RRC can have parameters required for the trafficvolume measurement. Then, the UE-RRC requests the UE-MAC to carry outthe traffic volume monitoring (S3). In this instance, the UE-RRCprovides the UE-MAC with a primitive CMAC_MEASUREMENT_REQ, containing ameasurement report mode parameter, and a measurement period parameter.If the measurement report mode is a periodic mode, a report intervalparameter is added thereto, and if the measurement report mode is anevent trigger mode, an upper critical value TH_(U) parameter and a lowercritical value TH_(L) parameter are added thereto. The upper criticalvalue TH_(U) parameter denotes a greatest boundary traffic volume inreporting measurements to UE-MAC, and the lower critical value TH_(L)parameter denotes a smallest boundary traffic volume in reportingmeasurement to the UE-MAC. Then, the UE-RLC provides the UE-MAC withstates of respective buffers, and its own data through the primitiveRLC_DATA_REQ at fixed intervals (S4). In this instance, as shown in FIG.2, respective buffers are at transport RLC buffer 1, 2, and 3 states,and data inclusive of the respective buffer states are provided througha dedicated traffic channel (DTCH). If the present measurement reportmode is a periodic mode, the UE-MAC receives results of measurements atthe transport RLC buffers 1, 2, and 3, and results of measurements atits transport MAC buffers 4, and 5, and provides these to the UE-RRC,periodically. (S5). Conversely, if the present measurement report modeis an event trigger mode, the UE-MAC checks if the results ofmeasurements at the transport RLC buffers 1, 2, and 3, and the resultsof measurements at its own transport MAC buffers 4, and 5 either exceedthe upper critical value TH_(U) or are lower than the critical valueTH_(L). If the results are outside the bounds TH_(U) and TH_(L), thenthey are reported to the UE-RRC (S5).

In the foregoing step S5, the UE-MAC uses the primitiveCAMC_MEASUREMENT_IND, together with the following parameters inreporting to UE-PRC. First, a sum of data existing at the transport RLCbuffers 1, 2, and 3, and the transport buffers 4, and 5 corresponding tothe traffic volume transported through the CCTrCH of the PHY is used. Inother words, a sum of data existing at buffers of all transport channelsand all data existing at buffers of logical channels, multiplexed by theCCTrCH, is used. The sum of data forms the measurement results reportedto the UE-RRC described in the step S5. As other parameters, states ofrespective buffers the UE-RLC provides to the UE-MAC at every intervalthrough the primitive RLC_DATA_REQ are used. That is, the amounts ofdata corresponding to respective radio access bearers RAB1, RAB2, andRAB3 are used. In this instance, as statistic values obtained bymeasuring respective buffer data for a given time period, averages anddeviations of amounts of data existing at respective buffers are used.As another parameters, averages and deviations of amounts of traffictransported through respective transport channels, and statistics ofmeasurement of respective channels for a given time period are used.

Then, upon reception of the measurement results on the buffer statesfrom the UE-MAC, the UE-RRC provides the measurement results on thebuffer states to the UTRAN-RRC (S6). In this instance, the measurementresults are provided through the DCCH, and primitiveMEASUREMENT_REPORT_MESSAGE is used.

Finally, the UTRAN-RRC controls the radio access bearer with referenceto, or according to, a result of the report of the measurement results.

The radio access bearers may be controlled by bearer reconfiguration,transport channel reconfiguration, physical channel reconfiguration, andTFC (Transport Format Combination) (S7). The bearer reconfiguration isrequired for correcting transport channels of the RLC, and MAC, and aconfiguration of the PHY entirely, and the transport channelreconfiguration is required for correcting the transport channel of theMAC and a configuration of the PHY. The physical channel reconfigurationis also required for correcting a configuration of the PHY. Thus, uponcompletion of the procedure for controlling the radio access bearers,the UTRAN_RRC provides new critical values to the UE-RRC, and the UE-RRCprovides the new critical values to the UE-MAC. According to this, theMAC uses the new critical values provided thereto in carrying out thetraffic volume monitoring function. By the way, if the received criticalvalue drops below a specific level continuously while the MAC carriesout the traffic volume monitoring function continuously and MAC receivesthe new critical values continuously, the transport channel type ischanged from a Dedicated Channel (DCH) to a Random Access Channel(RACH). That is, the form or type of transport channel is switched.

FIGS. 4A-4C illustrate how states of buffers in protocol entities in atraffic volume monitoring process change with time. FIG. 5 illustratesthe radio interface protocol architecture after the switching of atransport channel type occurs in the traffic volume monitoring process.From FIG. 5, it can be seen that the PDU (Protocol Data Unit) of the RLCis transported, not through the dedicated MAC (MAC-d), but through acommon MAC (MAC-c).

FIG. 6 illustrates a flow chart showing a process for monitoring trafficvolume for controlling radio access bearers in accordance with apreferred embodiment of the present invention. In order to makeexplanation of FIG. 6 clearer, the explanation also will refer to FIGS.2-5.

First, the MAC is provided with measurement parameters, inclusive of theupper critical value TH_(U) and the lower critical value TH_(L) providedfrom the RRC (S10). Basically, the MAC is provided with a RLC PDU fromeach of the RLCs which transports different radio access bearers RAB1,RAB2, and RAB3, and, at the same time, a state of each of the transportRLC buffers 1, 2, and 3 corresponding to respective radio access bearersfrom the RLC. Then, the MAC measures the a sum of data existing at thetransport RLC buffers 1, 2, and 3, and the transport MAC buffers 4, and5, which corresponds to the traffic volume transported through theCCTrCH (S11). Then, the MAC compares the traffic volume measurement ofthe channel CCTrCH to the upper critical value TH_(U) and the lowercritical value TH_(L) provided from the RRC (S12). If the measuredtraffic volume of the channel CCTrCH is a value falling between theupper critical value TH_(U) and the lower critical value TH_(L), thetraffic volume measurement of the channel CCTrCH is measured at fixedintervals (for example, at every 10 ms). However, if the traffic volumemeasurement of the channel CCTrCH falls outside of the range between theupper critical value TH_(U) and the lower critical value TH_(L), thenthe result of the traffic volume measurement of the channel CCTrCH isprovided to the RRC (S13). Then, the RRC undertakes a procedure forcontrolling the radio access bearers based on the traffic volumemeasurement of the channel CCTrCH provided thereto. The procedure forcontrolling the radio access bearers has been explained already.

As has been explained, the method for active control of a radio accessbearer in a mobile communication system of the present invention has thefollowing advantages.

A procedure for controlling radio access bearers is provided in moredetail over the traffic volume monitoring. Therefore, establishment,sustenance, and cancelation of radio resource access can be carried outefficiently in the radio interface protocol architecture according totraffic volumes of the RLC and MAC, which are sub-layers of the secondlayer.

And, the functions of establishment, sustenance, and cancelation of theradio access bearers and the radio resources required for radio resourceaccess can be carried out more efficiently.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the method for controlling aradio access bearer in a mobile communication system of the presentinvention without departing from the spirit or scope of the invention.Thus, it is intended that the present invention cover the modificationsand variations of this invention provided they come within the scope ofthe appended claims and their equivalents.

1-17. (canceled)
 18. A method for controlling radio bearers in a mobilecommunication device having a radio resource control layer, a radio linkcontrol layer, a medium access control layer, and a physical layerbeneath the radio resource control layer in succession, comprising:measuring traffic volume between the radio link control layer and themedium access control layer; comparing the measured traffic volume to atleast one reference value, that at least one reference value includingat least one of an upper critical value and a lower critical value;reporting traffic volume information associated with the measuredtraffic volume for each radio bearer to the radio resource layer, if acondition is satisfied between the measured traffic volume and the atleast one reference value; and controlling the radio bearers by theradio resource control layer according to the traffic volumeinformation.
 19. The method of claim 18, wherein the condition issatisfied when the measured traffic volume is larger than the uppercritical value.
 20. The method of claim 18, wherein the condition issatisfied when the measured traffic volume is smaller than the lowercritical value.
 21. The method of claim 18, wherein the steps ofmeasuring, comparing, and reporting are performed in the medium accesscontrol layer.
 22. The method of claim 18, further comprising receivinga measurement control message from a radio resource control layer of anetwork communicating with the mobile communication device.
 23. Themethod of claim 22, wherein the measurement control message includes theat least one of the upper critical value and the lower critical value.24. The method of claim 18, wherein the traffic volume information is atleast one of the measured traffic volume, an average of the measuredtraffic volume, and a variance of the measured traffic volume.
 25. Themethod of claim 24, wherein the measurement control message furtherincludes a time interval for calculating one of the average of themeasured traffic volume, and the variance of the measured trafficvolume.
 26. The method of claim 18, wherein the radio resource controllayer controls the radio bearers by using at least one of radio bearerreconfiguration, transport channel reconfiguration, and physical channelreconfiguration.
 27. The method of claim 18, wherein the step ofmeasuring traffic volume is performed on every transmission timeinterval (TTI).
 28. A method for controlling radio bearers in a mobilecommunication device having a radio resource control layer, a radio linkcontrol layer, a medium access control layer, and a physical layerbeneath the radio resource control layer in succession, comprising:measuring traffic volume between the radio link control layer and themedium access control layer; reporting traffic volume informationassociated with the measured traffic volume for each radio bearer to theradio resource control layer, when a reporting period is elapsed; andcontrolling the radio bearers by the radio resource control layeraccording to the traffic volume information.
 29. The method of claim 28,wherein the steps of measuring and reporting are performed in the mediumaccess control layer.
 30. The method of claim 28, further comprisingreceiving a measurement control message from a radio resource controllayer of a network communicating with the mobile communication device.31. The method of claim 30, wherein the measurement control messageincludes the reporting period.
 32. The method for claim 28, wherein thetraffic volume information is at least one of the measured trafficvolume, an average of the measured traffic volume, and a variance of themeasured traffic volume.
 33. The method of claim 32, wherein themeasurement control message further includes a time interval forcalculating one of the average of the measured traffic volume, and thevariance of the measured traffic volume.
 34. The method of claim 28,wherein the radio resource control layer controls the radio bearers byusing at least one of radio bearer reconfiguration, transport channelreconfiguration, and physical channel reconfiguration.
 35. The method ofclaim 28, wherein the step of measuring traffic volume is performed onevery transmission time interval (TTI).
 36. A method for controllingradio bearers in a mobile communication device having a radio resourcecontrol layer, a radio link control layer, a medium access controllayer, and a physical layer beneath the radio resource control layer insuccession, comprising: transferring a measurement control message tothe medium access control layer, the measurement control messageincluding a measurement report mode, wherein the measurement report modeis at least one of an event trigger mode and a periodic mode; receivingtraffic volume information from the medium access control layeraccording to the measurement report mode, the traffic volume informationbeing associated with traffic volume between the radio link controllayer and the medium access control layer; and controlling the radiobearers according to the traffic volume information.
 37. The method ofclaim 36, wherein the measurement control message further includes theat least one of an upper critical value and a lower critical value. 38.The method of claim 36, further comprising, when the measurement mode isthe periodic mode: checking whether a reporting period is elapsed in themedium access control layer.
 39. The method of claim 21, wherein themeasurement control message further includes the reporting period. 40.The method of claim 36, wherein each step is performed in the radioresource control layer.
 41. The method of claim 36, wherein the trafficvolume information is at least one of the traffic volume, an average ofthe traffic volume, and a variance of the traffic volume.
 42. The methodof claim 24, wherein the measurement control message further includes atime interval for calculating one of the average of the measured trafficvolume, and the variance of the measured traffic volume.
 43. The methodof claim 36, wherein the radio resource control layer controls the radiobearers by using at least one of radio bearer reconfiguration, transportchannel reconfiguration, and physical channel reconfiguration.